This invention relates to optical transmitters, receivers, and transceivers.
More specifically, this invention relates to data links in optical transmitters, receivers, and transceivers.
Optical transmitters, receivers and transceivers are used for converting electrical data into optical data for transmission on optical fibers and for converting optical data back into electrical data for processing by network equipment. Normally, an optical transmitter includes a light source, such as a laser driver and a laser diode, and an optical receiver includes a light conversion device, such as a post amplifier, a trans-impedance amplifier and a PIN photodiode or an APD. The transmitter or receiver is generally mounted on a network circuit board to interface with other data processing IC chips, such as a serializer or de-serializer, a data framer for coding, such as 8B/10B coding, and a higher level data control IC. This type of structure, however, fails to, perform when the data transport rate reaches around 10 Gbps or beyond, as the electric traces on the printed circuit board introduce noises and jitters and distort the signal integrity at such a high frequency.
Current technology requires that a serializer and de-serializer be integrated into the transmitter and receiver module or modules to allow electrical interfaces to operate at lower frequency. As an example, for an OC192 data rate, the electrical interfaces for the data link module will require 16 channels of 622 Mbps. The module, which is called a fiber optical transponder, can then be mounted onto the board to interface with other IC chips to fulfill the network management function. Consequently, the module requires many electrical interfaces, typically with more than 50 pins. The large number of pins and the extra internal circuitry dictates that the module size is large. The power consumption is also a serious issue.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object the present invention to provide a new and improved high-speed optical data link.
Another object of the present invention is to provide a new and improved high-speed optical data link capable of conveying data at around 10 Gbps rates or beyond.
And another object of the present invention is to provide a new and improved high-speed optical data link that is simple and relatively inexpensive to manufacture.
Still another object of the present invention is to provide a new and improved high-speed optical data link that is smaller than prior art devices and less electrical pin counts capable of conveying information at similar rates.
Briefly, to achieve the desired objects of the present invention in accordance with a preferred embodiment thereof, provided is a high-speed optical data link including a system board with first and second ASICs mounted thereon. The first ASIC includes a clocking and an equalization function for recovering distorted data. The second ASIC is electrically coupled to the first ASIC for conveying electrical signals therebetween and the second ASIC includes one of a clocking and an equalization function for recovering distorted data.
In a more specific embodiment, a high-speed optical data link includes a first ASIC coupled to convey electrical information to a remote circuit and a second ASIC electrically coupled to the first ASIC for conveying electrical signals therebetween. A fiber optic receiver module is mounted on the system circuit board and includes a photo diode positioned to receive optical signals from a remote source, a trans-impedance amplifier electrically coupled to the photo diode, and a post-amplifier, such as a limiting amplifier or an auto-gain control circuitry, electrically coupled to the trans-impedance amplifier and to the second ASIC. The second ASIC includes a clocking and an equalization function for data integrity and the first ASIC includes a function for recovering distorted data through the same clocking and an equalization scheme as provided by the second ASIC.
In another more specific embodiment a high-speed optical data link also includes a first ASIC coupled to receive electrical information form a remote circuit and a second ASIC electrically coupled to the first ASIC for conveying electrical signals therebetween. A fiber optic transmitter module mounted on the system circuit board includes a laser positioned to convey optical signals to a remote source and a laser driver electrically coupled to the laser and to the second ASIC. The first ASIC includes a clocking and may include an equalization function for data transmission and the second ASIC includes an equalization function for recovering distorted data through the same clocking. It should be noted that both of the last two embodiments described can, optionally, be packaged and included on a common board with the first and second ASICs being common.
The embodiments described above include a novel method of electrically communicating information at 10-gigabits per second or beyond on a circuit board. The method includes the steps of providing a system circuit board including a first position and a second position, receiving electrical signals from an external source at the first position on the system circuit board, clocking and equalizing the electrical signals on the system circuit board for providing signals with integrity, conveying the equalized signals to the second position on the system circuit board, and receiving the equalized signals at the second position and recovering distorted signals using a de-clocking and re-timing step.